1. Field of the Invention
The present invention relates to a performance information analyzer adapted for use in performing apparatus such as an electronic musical intrument, an electronic piano player, an electronic musical multimedia system or the like, and more particularly to a performance information analyzer for analyzing performance information including a plurality of tone pitch information data of a musical tune into a plurality of performance parts and a chord detection device associated with the performance information analyzer for detecting a chord on a basis of the analyzed performance parts.
2. Discussion of the Prior Art
In recent years, there has been proposed an electronic musical instrument for harmonizing automatic accopaniment with performance played on a keyboard. In this kind of electronic musical instruments, it is required to detect a chord for determining a tone pitch of the accompaniment tone. For this reason, the chord is determined on a basis of performance information applied from the keyboard or key-codes of depressed keys of the keyboard. In general, melody performance is played at a higher tone area of the keyboard where mainly key-codes of non-harmonic tones relative to the chord are detected. Accordingly, the keyboard is immaginarily divided into a left-hand key area for the lower tone and a right-hand key area for the higher tone so that a chord is detected on a basis of key-codes of depressed keys at the left-hand key area.
As mentioned above, there is a tone area suitable for detection of the chord in a case that the chord is detected on a basis of tone pitch information such as the key-codes. Since the tone area changes in accordance with performance of a musical tune, there has been proposed a method capable of enhancing accuracy in detection of the chord under control of a manual switch arranged to be operated by a user for changing a boundary between the left-hand key area and the right-hand key area. In such an electronic musical instrument, however, the user is obliged to operate the manual switch during performance of the musical tune, resulting in a difficulty in operation of the manual switch.
On the other hand, almost all musical tunes can be divided into a plurality of performance parts such as a melody part or a bass part which include an appropriate performance part for detection of the chord. Therefore, if performance information can be analyzed into the plurality of performance parts, it is possible to enhance accuracy in detection of the chord in accordance with the performance part Assuming that automatic performance information could be analyzed into a pluarlity of performance parts, only a desired performance part can be muted to effect the automatic performance, and a function (so called a minus-one function) capable of harmonizing the keyboard performance with the automatic performace can be provided in a simple manner for practice of the user. Furthermore, in case the performance information could be analyzed into the plurality of performance parts as described above, it is able to add another melody to the performance information or to substitute another melody for a portion of the performance part for effecting an automatic arrangement.